And a spokeswoman for the road safety charity, Brake, said smoking while driving meant people were not concentrating on the road.

"All that can add up to not having proper control of your vehicle or dangerous driving."

She said it might be useful to have a law banning smoking in the same way there was in force regarding using hand-held mobile phones.

But Neil Rafferty, Scottish spokesman for Forest, the pro-smokers' rights group, said: "We don't think that children should be exposed to smoke in a car but a ban would be a waste of police and court time.

"Would it be OK if you opened the sunroof or a window while smoking? It's an impractical suggestion.

"People like those at the Royal College of Paediatrics and Child Health should be more realistic about what is possible."

A Department of Health spokesman said it would look at whether current anti-smoking laws needed to be extended.

He added: "We would always strongly recommend that people do not smoke in cars